Myelin sheath is a layer of lipid cell membrane that covers sheath nerve fiber axon outside and consists of myelin sheath cells, which main physiological function is to act “insulation” and protection functions on nerve axon, and facilitates rapid transmission of nervous impulses. Demyelinating disease is a group of disorders characterized by myelinoclasis of nerve fiber as main pathological change, which can either implicate central nervous system, or peripheral nervous system. This disease has main pathological features of: (1) nerve fiber myelinoclasis, presented in multiple small disseminated foci, or a relatively large focus formed by one or more foci in fusion; (2) demyelination lesions are distributed in alba, spinal cord or peripheral nerves, infiltrating in coatsleeve like form along inflammatory cells around veinlet. This kind of diseases include multiple sclerosis, optical neuromyelitis, acute disseminated encephalomyelitis, diffuse sclerosis, concentric circle sclerosis, leukodystrophy, central pontine myelinolysis, acute inflammatory demyelinating polyneuropathy, chronic inflammatory demyelinating polyneuropathy; and demyelinating diseases caused by other factors, including but not limited to leukoencephalopathy caused by ischemia-anoxia diseases, subacute combined degeneration caused by nutrition deficiency diseases, subacute sclerosing panencephalitis or progressive multifocal leukoencephalopathy caused by viral infection, diabetic neuropathy (this disease is mainly presented demyelination lesion), nervous lesions of systemic lupus erythematosus (this disease is mainly presented in demyelination lesion). The research of an effective drug for alleviating myelination and promoting myelin sheath plerosis may provide an important means for preventing demyelination diseases in central and peripheral nervous systems caused by various factors.
Epimedium is a perennial herb berberidaceae plant, and is a traditional Chinese medicine for reinforcing kidney. Epimedium extract or Epimedium flavanoids are main effective components of Epimedium. Epimedium flavanoids contain icariin, baohuoside, epimedin, in which icariin is a main active component thereof.